An understanding of mitosis, its regulation and its mechanics is central to many areas of medicine having to do with cell growth and division, e.g., cancer, embryological development and human genetics. The objective of this project is a better understanding of the mechanics and regulation of nuclear division. The immediate goal is to identify and characterize the products of specific genes involved in nuclear division by using DNA mediated transformation to complement specific mitotic mutations in Aspergillus nidulans. Genes will be cloned, sequenced and their products characterized by hybrid selection and translation of complementary messenger RNA's. Antibodies to the protein products of these genes will be prepared and used to localize the gene products in cells.